The CB ones are the only ones to consider. They use an aluminum hub with an iron disc bolted to it so the mass is kept as low as possible.
The EMPI rotor is a massive single piece of cast iron that weighs more than your engine's flywheel! The EMPI rotors act like huge flywheels, good thing they have a disc brake on them to help slow them down. The extra weight in them increases the sprung mass of each wheel. The result is that it makes the car ride worse.
